Nearly 1,000 Islamic State (IS) extremists have been killed in RAF air strikes in Iraq and Syria in the last 18 months, according to new figures.

Some 974 militants in Iraq have been killed in action since the UK bombing campaign began in the country in September 2014, data released by the Ministry of Defence (MoD) under Freedom of Information laws showed.

A further 22 jihadists have been killed in Syria since December after Parliament voted to extend air raids to attack the extremists’ stronghold.

The MoD said there had been no civilian casualties and the figures for enemy casualties, which also include 98 injured militants, were estimates based on “post-strike analysis” because the UK cannot visit strike sites to verify the numbers dead.

The RAF’s campaign has intensified in recent months, with Typhoon and Tornado fighter jets attacking infrastructure targets such as oilfields and bomb factories as well as mortar and sniper positions.

The latest figures show 318 jihadists have been killed in the first three months of this year in both Iraq and Syria, compared with 92 in the same period last year.

In one strike over eastern Syria on April 22, Reaper drones destroyed an improvised weapons factory and workshop used for constructing car bombs, the MoD said.

IS, also known as Isil or Daesh, has seized large swathes of territory in both countries, declaring a self-styled Islamic caliphate.